public class homework06 {

        public static class Test{
            public static void main(String []args) {
                int x=2,y=1,s=0;
                for(int i=0;i<20;i++) {
                    double m= x/y;
                    s+=x/y;
                    x=x+y;
                    y=x;
                }
                System.out.print("这个数列的前20项和是"+s);
            }
        }

    }


